Ryan Mallett has attempted just four passes in his NFL career. / David Butler II , USA TODAY Sports

by Tom Pelissero, USA TODAY Sports

by Tom Pelissero, USA TODAY Sports

Ryan Mallett is headed to Houston for a reunion with coach Bill O'Brien.

The Texans acquired the fourth-year quarterback from the New England Patriots on Sunday, a person with knowledge of the deal confirmed to USA TODAY Sports.

The person spoke on the condition of anonymity because neither team had announced the trade, which was first reported by NFL.com.

Terms weren't disclosed, but it doesn't appear the Patriots got much. ESPN.com reported the Texans gave up a sixth-round draft pick. NFL.com and the Houston Chronicle reported it's a conditional seventh-round pick in 2016.

Mallett, 26, was a third-round pick by the Patriots out of Arkansas in 2011 and spent the past three seasons as Tom Brady's backup. That role now goes to Jimmy Garoppolo, the Patriots' rookie second-round pick from Eastern Illinois.

O'Brien was with the Patriots as an offensive assistant in 2011, Mallett's rookie season. The Texans plan to start veteran Ryan Fitzpatrick this season and used a fourth-round pick in May on Tom Savage.

To make room on the roster, the Texans waived second-year quarterback Case Keenum, who started eight games for them last season.